Estrogens: a new player in spermatogenesis.

The mammalian testis serves two main functions: production of spermatozoa and synthesis of steroids; among them, estrogens are the end products obtained from the irreversible transformation of androgens by aromatase. The aromatase is encoded by a single gene (cyp19) in humans which contains 18 exons, 9 of them being translated. In rat the aromatase activity is mainly located in Sertoli cells of immature animals and then in Leydig cells of adults. Moreover rat germ cells represent an additional source of estrogens: the amount of P450arom transcript is 3-fold higher in pachytene spermatocytes (PS) compared to gonocytes or round spermatids (RS); conversely, aromatase activity is more intense in haploid cells. Male germ cells of mice, bank vole, bear and monkey express also aromatase. In man besides Leydig cells, we have shown the presence of a biologically active aromatase and of estrogen receptors in ejaculated spermatozoa and in immature germ cells. Concerning aromatase, a 30% decrease of the amount of mRNA is observed in immotile compared to motile sperm fraction from the same sample; moreover the aromatase activity is also diminished of 34%. In asthenoteratozoospermic and teratozoospermic patients the aromatase gene expression is decreased by 67 and 52%, respectively when compared to normospermic controls. Statistical analyses between the sperm morphology and the aromatase/GAPDH ratio have revealed a high degree of correlation (r=-0.64) between the ratio and the percentage of abnormal spermatozoa (especially microcephaly and acrosmome malformations). Alterations of sperm number and motility have been described in men genetically deficient in aromatase, which together with our data, suggest a likely role for aromatase/estrogens in the acquisition of sperm motility. Therefore besides gonadotrophins and testosterone, estrogens produced locally should be considered as a physiologically relevant hormone involved in the regulation of spermatogenesis and spermiogenesis

Régulation de l'expression du gène de l'aromatase dans les cellules testiculaires de rat

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Three promoters PII, PI.f, and PI.tr direct the expression of aromatase (cyp19) gene in male rat germ cells

International audienc

The promoter(s) of aromatase gene in male testicular cells

International audienc

Aromatase and estrogen receptors in male reproduction

International audienc

Protective effects of estrogens and caloric restriction during aging on various rat testis parameters

Aim: To investigate the effects of 17 beta-estradiol (E2), Peganum harmala extract (PHE) and caloric restriction (CR) on various testis parameters during aging. Methods: Twelve-month-old male rats were treated for 6 months with either E2 or PHE, or submitted to CR (40%). Results: Our results show that estrogens and CR are able to protect the male gonad by preventing the decrease of testosterone and E2 levels as well as the decrease of aromatase and estrogen receptor gene expressions. Indeed, E2, PHE and CR treatments induced an increase in the superoxide dismutase activities and decreased the activity of testicular enzymes: gamma-glutamyl transferase, alkaline phosphatase, lactate deshydrogenase as well as the aspartate and lactate transaminases in aged animals. In addition, the testicular catalase and gluthatione peroxidase activities were enhanced in E2, PHE and CR-treated rats compared to untreated animals at 18 months of age. Moreover, the positive effects of estradiol, PHE and CR were further supported by a lower level of lipid peroxidation. Recovery of spermatogenesis was recorded in treated rats. Conclusion: Besides a low caloric diet which is beneficial for spermatogenesis, a protective antioxydant role of estrogens is suggested. Estrogens delay testicular cell damage, which leads to functional senescence and, therefore, estrogens are helpful in protecting the reproductive functions from the adverse effects exerted by reactive oxygen species (ROS) produced in large quantities in the aged testis

Age-related decrease in aromatase and estrogen receptor (ER alpha and ER beta) expression in rat testes: protective effect of low caloric diets

Aim: To examine the effects on rat aging of caloric restriction (CR1) and undernutrition (CR2) on the body and on testicular weights, on two enzymatic antioxidants (superoxide dismutase and catalase), on lipid peroxidation and on the expression of testicular aromatase and estrogen receptors (ER). Methods: CR was initiated in 1-month-old rats and carried on until the age of 18 months. Results: In control and CR2 rats an age-related decrease of the aromatase and of ER (alpha and beta) gene expression was observed; in parallel a diminution of testicular weights, and of the total number and motility of epididymal spermatozo was recorded. In addition, aging in control and CR2 rats was accompanied by a significant decrease in testicular superoxide dismutase, catalase activities, and an increase in lipid peroxidation level (thiobarbituric acid reactive substance), associated with alterations of spermatogenesis. Conversely, caloric restriction-treatment exerted a protective effect and all the parameters were less affected by aging. Conclusion: These results indicate that during aging, a low caloric diet (not undernutrition) is beneficial for spermatogenesis and likely improves the protection of the cells via an increase of the cellular antioxidant defense system in which aromatase/ ER could play a role

Aromatase in testis: expression and role in male reproduction

International audienc

Estrogen: Roles in spermatogenesis

International audienc

Estrogens: a new player in spermatogenesis.

The mammalian testis serves two main functions: production of spermatozoa and synthesis of steroids; among them, estrogens are the end products obtained from the irreversible transformation of androgens by aromatase. The aromatase is encoded by a single gene (cyp19) in humans which contains 18 exons, 9 of them being translated. In rat the aromatase activity is mainly located in Sertoli cells of immature animals and then in Leydig cells of adults. Moreover rat germ cells represent an additional source of estrogens: the amount of P450arom transcript is 3-fold higher in pachytene spermatocytes (PS) compared to gonocytes or round spermatids (RS); conversely, aromatase activity is more intense in haploid cells. Male germ cells of mice, bank vole, bear and monkey express also aromatase. In man besides Leydig cells, we have shown the presence of a biologically active aromatase and of estrogen receptors in ejaculated spermatozoa and in immature germ cells. Concerning aromatase, a 30% decrease of the amount of mRNA is observed in immotile compared to motile sperm fraction from the same sample; moreover the aromatase activity is also diminished of 34%. In asthenoteratozoospermic and teratozoospermic patients the aromatase gene expression is decreased by 67 and 52%, respectively when compared to normospermic controls. Statistical analyses between the sperm morphology and the aromatase/GAPDH ratio have revealed a high degree of correlation (r=-0.64) between the ratio and the percentage of abnormal spermatozoa (especially microcephaly and acrosmome malformations). Alterations of sperm number and motility have been described in men genetically deficient in aromatase, which together with our data, suggest a likely role for aromatase/estrogens in the acquisition of sperm motility. Therefore besides gonadotrophins and testosterone, estrogens produced locally should be considered as a physiologically relevant hormone involved in the regulation of spermatogenesis and spermiogenesis